1. Field of the Invention
The present invention relates generally to Power over Ethernet (PoE), and more particularly to a PD controller for PoE systems with increased cable length.
2. Background Art
Ethernet communications provide high speed communications between data terminals.
Power over Ethernet (PoE) systems enable power transmission over the same transmission lines that carry data in an Ethernet. Generally, power is generated at a Power Source Equipment (PSE) side of the PoE system and is carried over the data transmission lines to a Powered Device (PD) side of the PoE System.
A PSE controller is typically used at the PSE side to enable power management functions of the PD. For example, a PSE controller may be used to detect whether a valid PD device is active and to manage power flow to the PD. Further, at either side of a PoE system, a transceiver physical layer (PHY) is available to transmit and receive data over the transmission lines.
Current IEEE compliant PoE systems support cable lengths up to approximately 100 meters only. There is a need therefore for improved PoE systems that support greater cable lengths.